SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8797faea766eb1f338f8613a580759327a4cdcdef9e75f1c6be10a391bc01c' 
  AND token = 'oHnTGMerUVbF29qTTrs4IAsbJ5mdeqJA2X9ngmtJtyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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