SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9067ab0a2ed5d479697a5706958e1abae42e3c83437f843ac2acc96eccf54e66' 
  AND token = '892GC+SFD77WItFpaFZxRpk3+3WcNmtlZv7tn8UxehM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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