SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f229fc0193ac8be6bbee2a4ef39031ffe87a0b956072955dcd2fa4a619068e42' 
  AND token = '3TwriaGI8K8pqHbQbRBAgJFQxSoW6t/6PgiwuBuGQjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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