SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15541414675db363c7d753b0b78d6e902e77971c4a723b5135559c5d83df4b40' 
  AND token = 'nxSNbpO9aQOp481MyKbd859/WjdTEPnAo04wBa/G9DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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