SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2e38becf4fb13c561efdd2614b47f25548d6d1025c045c7f0c982c78d87747' 
  AND token = 'iq7tEFr6n52XmU2tcc3AreLFN07XxDtJtbUZJGjN+Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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