SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a360f70f9f9c64f2ba11335b42b1d6c4db4f74001baf9ebd5dc4da266f058150' 
  AND token = 'umPaTws+cXtlGjlnm5AQYp995vdNXAzMgCJztRKGLag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}