SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a506fe329bed2ff07d39e475d05044df16476dca1dcf4e83f39b60953d7c5268' 
  AND token = 'yEcAzj8RNOYV3ovkxDi4KpfJeAQKlRQZXFgjj5MKX88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}