SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b0d1e314e1258dc03924034cd21dba1c94ad47400c73b38ff31cd7d1f5a24e5' 
  AND token = 'sPg/UHKyRs/SLSwiskrdkObFlQYaDycRkLEwQ3hJqxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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