SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4bb8fae82a4777e84bae34179ede90fefa41d8d6f2c70ac08ce1be80c2dbe13' 
  AND token = '4gWqJiCTwDLQGOGeYhWVtoK+Td7U6UGHRAG8GXkv66o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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