SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16fca62e48be4f20e56e1159b7656061087a43169757bcfacb54ad6f30433395' 
  AND token = 'kMvOkU8+3m763ML+eXqpNFtLVqaulAQCwViH8DaNjr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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