SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b0f4170b5d9b15ea94883c91f11ede79a5e38760e79fc48fe520221b5e43a1c' 
  AND token = 'zbNq+Z0jSRUhwa6RzA2v/Q9xYfoVuxgyLAnkOcjYMq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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