SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ccefbe8c34f752a358f8d3444297f277e91363122fd4d224569471a689efcca' 
  AND token = 'xvyx3zzPIe4+Yi7DNz8OzxO7i8FNuKZgqbZMgLdKTYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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