SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc667d6d23d0b127bbed02d86c3f42f909b65f867929681be7d10b82fb0cbb3' 
  AND token = 'RGdNH7mkZi/QFxShDKq+F4L+eVjPlBF+BTPynJAUzbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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