SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94f3a63db598e3fce67a54078b7770317b9ccc86d3ccea6a358197eee7c2af03' 
  AND token = 'sMp9eQoFUcKHi+lVgzcEQfcw1xflPvZzY0b9Koby7DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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