SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9d0329aa2217a65a0c3d9ceddbd62ed0cdbb7281ab2ea8cf2078e6a211a9467' 
  AND token = 'cdN9jryywx2UaAVunsrSJll9GVop4wfbSfYFadEz3Bo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}