SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '087d88bcda0726ba8165d4b25b5137113a2e2909027e230cf218cefd0441b244' 
  AND token = 'KKe+14PKsJGp3IjKqA5kP+ahxBpvQD4QpG8smpxKqCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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