SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9542d293a04d146f0b557bd8113901f1950836cc291472076b6b02f3f95f9487' 
  AND token = 'k26nnDjQy6MXZPIDUxcgtyljxkhFj5vNRIGKT/XSww8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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