SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56054f66448e18d514378529c720a83fe5e63f97b8a1b3b88f22bb0b9d251950' 
  AND token = 'uvNbj7igtsd/LPz+UbLd+mEY7Yyow1e8sDXymHYtGRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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