SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3fe9c5f0495572dfdb59297505c28e25a761ae7575ba150951221defccc4329' 
  AND token = 'vna+106tmACv1KAwl6e2UZv8z09CSevOmPmHZMN1zQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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