SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f8fc8d0b78d76409320953d5d257f5145fb981260f3f5b182b1335b759c5a2e' 
  AND token = '0Oi6PBt/tA69ACGQ/U/TJhyL+kereSoyAyRsNUWPCIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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