SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3523c4b1032edcf590beb3ececc04adb99c76df5dd8d7bacd0c12b6f7ea4725' 
  AND token = 'JEZYDzkSBMNMtNs0lex+Po/Uf5pBHRcpN1KTSHJgswo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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