SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e54f83a7ee2b570a626b3fb074e937e4e65d7096861f967dc636615a5d01833' 
  AND token = 'T6gTboCxu3DaMf0D63nWsWaYhwGyRjPPUFb1+xLasDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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