SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e0a08bacbb9b83095792f72f6669c693d1334f3404c9bfc4c1ac186ea641dbb' 
  AND token = 'yyzBp7z985oSgLahoUfZnJmwCDUERHv0fzbmKMYOUQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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