SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11fab990d747d8bfa8ab42cd25cd9856dab3891eafe964806c37e59282a1e85a' 
  AND token = 'd8nqjalb54A3DgsRoBu5kWEKdonoa/3CJwCpangsTLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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