SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49f28d28e125a8f6b1217c00b6395ca22a841e801252ac5a9b7cb661acb95af' 
  AND token = 'W5QtwMJiixhadAV0TRdgF8TBfUAcQ9EajoShtWRCom0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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