SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5983782835a72f0241062b2b82d8c453ccf45bca8295f9c03106930432b1f6f2' 
  AND token = 'aqMD/yGv0xUqqHjUs5BszD5OOJdANrQSmJScOgB6/Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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