SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eaa20193cf8b02fb919176bcfa307df2a0375643b464bd627629b4bc9736c53' 
  AND token = 'knP+YDVCj8VPHY69d0ZYW+NYIclJtw7qflzK0ugKMsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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