SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cc34bd99fd0297e31fb64a941a15444b20454b74d94686f49edca2253a4c08f' 
  AND token = 'HUKimLVLUXzdLKPfT62FZ+0RN7kiQevR/mEEavH7iLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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