SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b439cf0dd45d854ad2e27fcf9e1e0b6b3bffaf8c4c351717e344c0225ae98c60' 
  AND token = 'NMw1VyMCt66UvrNKPjd+l7XCy8c/ZmngYWL8QhwDkiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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