SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6280d872727bef283d7043801da9da2a2cc2db99bd6cacc181ec5104af85550' 
  AND token = 'ZwckLqC8ofjXpHP/E4BDRhtf+RELlFXolAnl/ETnQwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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