SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2138f8b1dd543013d0cfde61a17b2de12ba16f119fbebb430a872b3846779b4c' 
  AND token = 'cwK3oTxfdb1ZJGC/P8r8bRfbOkT8zlX+PZPnQXoFgJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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