SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '609695b1d6674000858d7a4af75d7cd5172afb73409c78538ae82b1dba24eeee' 
  AND token = '0oRKZY+sWk30crr6o8JbYIiEWfv0XbLJDBulpn0BVxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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