SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4818685ccd1873ae62bc784a4699046165b04bbec49038307c34075e9cf81971' 
  AND token = 'aHjCJ47IT/W7naowRkQePqGiCCz75lrGUVMy+WrAQcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}