SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4332241b75decb573fa93473ea946d501417ce02ecca95a5c1ac1ac634d5dd5' 
  AND token = 'LQ/OlLse9fz2pcIfDye3A+LUXWfd9ybHLJ9+nOxwTz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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