SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c8e643d2667b6b972a45b85eaacfd2d291db389b6b419b239838daf34a768fe' 
  AND token = 'DcBEINNkKbZg8siaBxDhmakGRq4RWA244rIver2ru18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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