SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd31eff52140048467b39d2bad70d2b176aa98ce6d344b1048bd8bd05ed5afcb' 
  AND token = '3ZcGVtloqqpwWPEgAEGpV4UULnxXGKJC72pkchZywJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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