SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74784f9ec5808cf0feeb8d63d4bc8b66c199364d5bf65ec8525568cd3f3d8090' 
  AND token = '9n+pCHpSnvGdpUNOU+jXBn4QTKgw5oceqgzZjd8ROuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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