SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1472999311193087f423dcdc5d524d2567fb7964688a0eee5de4662293768d2' 
  AND token = 't5aqYSxsdjBRiiZVX3BJl1Qh2JpMccZKpCgv0BUfPVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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