SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70ddb2373e8e1fb9c256d27bbd65caef16795e4aaf52d393605ef0592a56bda6' 
  AND token = 'ZI2pNvZxChT+HoGsEKDnwtYrIHcopGEmQBcY5uzrTTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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