SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52625896217b3c5e1400c5c85dbbac614c34352a89a53a0c2bb2dd9e0f881884' 
  AND token = 'Hf6kTOH2pLbdEl8vJEOcevERAf5OzhNUH1N7MYkWU1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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