SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c12bfce794300983626f3ad0cf98f169e2d2a45a2432f09051dfeca670e9118e' 
  AND token = 'YwxvRb0Dr7phunvGyStAuCY8Ccv40t2l/rrxnpGwgYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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