SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3f1396765197251bf272660080b7dc73dc4b0fc71ec415ed1c42abf5b726761' 
  AND token = 'Krg4zyacwXZI2WY7my0t77otZXQhFHk94FjT1LEQ++Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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