SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31e202801e397b25e0beb41ecbee0148be9dba402a41b5a28e120231f0b458a1' 
  AND token = '4qPmgMrXl/CILhsB2KlIWRe4hTkeEPkwgT2eep6j4Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}