SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6880d84b6c9b4bc1049c4bf13ec1e068b92a760ffe4dee00d80b182324feb43' 
  AND token = '842dmd89C9TNGCDKk3DbbjySL3dW8aUoL1yfDSiNO+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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