SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fb8c0e491becd7f4428c5b092a17026b74356863acaf29920eadc94133456cd' 
  AND token = 'kP+ZnwHwEdB/8PJL2L5XuV5JXRjTadA8LLy5fzbYLNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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