SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33f57e3accb7b58020ff814041b4a53c5219a02831c50fbb12490042c938afb6' 
  AND token = '4KCj38tCG6EJi5hMXXTn6/lCZR1GArmm5orQRUbQc1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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