SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '457e6b382ad97ccacd6b1b870d3f47684df6e6dd91b378fc20be0ff662ae950e' 
  AND token = '2wGKOe1SGB3OAvMwIuBin/x44tHxuFzmCKm15aMxDcA=' 
  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"
    }
  }
}