SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71626a91fe35cca5ebf63359e171499114853ba665d1bd0d403460f5dcae6ec9' 
  AND token = 'VV8rZZuTPNGvsI6OJrpr+Vt+PCHgZjZSs8L9fw4UB0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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