SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '590473a7151b19baa1c3f30fc2531efc7558c86b57944c249aca49659d1909a0' 
  AND token = 'KT+LUcjcq3HroOfIDH+zrXLvKCnT0f1C9MJ3PHgRGWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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