SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '623f225d797a1b97757299918cca47a2657c8b4197f2c4cf1ff8b2a944f441e2' 
  AND token = '5VsLRRHkly2Ihzh/DH8eqg0JKavOZTNBI03VKGHhU0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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