SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd3ebf497872cfdba96dfb469b4444e4210623cc06333e685477f551e1ad4f6b' 
  AND token = '7TYBvThwbZWgYy0xcA43Ayl6Qz7bKJgolEXPV9j3Low=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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