SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc49519fe3042284b07d6223ae31e7f5f50a27008bac9fbd88f8bd8a3d9c76f0' 
  AND token = 'zj60/IIhqBjC0ubLMTOtpAFn+rHFDS14JtYTtmPhj+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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