SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f6ebc320473e6ae4650521db87b6fdd061053c1a3f836fd167227511506c143' 
  AND token = 'yUPXHYnMxlPxtPZtXaAHnpZdmI5DCYKobEXqgu77bvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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