SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d5e49a263f0efcd760738a2b57509d44f0f471a9796131a920199a36ebae178' 
  AND token = 'Pke4tzOE6tcVY55bfIU9ClYwBb1SdwXd71AfmGSX69I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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