SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '812162021b720ef9769031d93303feb0113062420dd04002714bff9f12dd6c4c' 
  AND token = 'jLv3sd/mIEk8NXfRsQFMmbo1q46ghBbo5pv9n3YVnEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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