SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dfd6d6938c4f492a3024ba30f9dcc3200dee805e43d788efd5d1c00dc500af0' 
  AND token = 'qZk4tEj+DdbHH33rGuLuyYXoFRrDqeskAFedjBS+1S0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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