SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63e98f4916877efd88480cf273e98e2bc54c25bbd5c01901ee4b21d871eec76d' 
  AND token = 'Ny8yY1bplQfGKvFWuT7uk5VchLuaoqUVLk3aevzXdbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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