SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc81c66a41a00ef11bd8366458589f74454772a76186b4058102cfbb832f5d07' 
  AND token = 'cIhXTgGlBhd6QNNd4sQTjXEDLgLiWgPk7ldPZJCxlD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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