SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df87cd2cbd01777abc4136cc57f11a1196a93c62bbed6825e87f5306594ae95d' 
  AND token = 'U1Rc5yb9F8IzRh/wKFRuoCJpXJXL4BbqF+DhXSALUXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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