SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08c652df732cf3801487a6560ea0615b22b057701fcab0f659446d7bb1626e06' 
  AND token = 'zB4aBqcKeVCVmphfD9hRARMJdPta9Urv2vMdqjGBVD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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