SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4091608461b23ecb9aa8ab59b63ad5b7654d14fb544adea89bfdb72dd3599878' 
  AND token = 'PKimdvTU223RNFtbXParJIecLYyani+KMM8U8lWQxec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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