SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e365c76dd4eb7acc2451f128842348288c9a16c3ceb031261a2629c2997987bd' 
  AND token = 'XtPlVUP4aQtHr7YWVd02TRrvmFVRHalcgFE1w0UT1o4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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