SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f5019317b322c7792c4f880469fe5b1796de4375111c0e0fcf9b40cd6755ff5' 
  AND token = '7SMPpjKw5xNqTPCv/W8zYrUmAeCLcfGNy9yOvVVU+7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}