SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b5d03af0a27b00db772972cb0d765cf620a4ff1fb8464a75f11daf4e7d94c62' 
  AND token = 'WKN8BqsvmGZgvhPb3HJK0SL+zWVanitRih0zlwh0uDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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