SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0bbaa4075b636816810f7bdfee969878fcc16bff2200edbe633286135afb987' 
  AND token = 'ccWJ8DInJ1gD/rVBcprAvr4MGJaNqh49OvCQEFfGIiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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