SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bc9770831e0ba5b20ba7e40fcd00aba85fb9195ab82868f567e2e41d34c5348' 
  AND token = 'hwyPXfCHz0LWsargDfA46r7AuUwvCpwrNWcJ65lmWRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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