SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fee87c4d4400c5f54fd4e107cb8926b19c46d83120ae798b83f33b5f90113c5' 
  AND token = 'aCTeUaBwN+OZbj9sQgQnr2WloLPrCNvLQgziR0qREqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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