SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9ea1bbe64f3db44c50e438e9473f35fef196d8187ce82207dcad9a5a86566cd' 
  AND token = 'p+YgyIlLKVATWfGiOvBZxWaX4UsutZvbecBDMVP2nO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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