SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b1ea8706964eb13d149507b61725e6cc9fb3609b8b46abbae9d605da07863eb' 
  AND token = 'T9GJUf2+iGsoJoRt13MAZ2x9yjWWWzPEk/hrbGsRbEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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