SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4b2e6b381b74222d3ac4f84e17229f029381fa9fc7d1e7d2669c0c8e129ea716' 
  AND token = 'lrQ98s/73PVhxpnr+HCW3oSjh66AzcjyMl4fTrSZ5Jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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