SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb5152df6f752f635f535a9e5c2c61ff5923eee427f65cbf7a34894e9d22bccf' 
  AND token = 'hMJyw5acpTZ6FORXrXI/ofjSjnbyTOOG7nbiOQDsdrY=' 
  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"
    }
  }
}