SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f92cdf65f135c0f41fab0a74074c9872eefab1d8645903995f3fcefaf4061b46' 
  AND token = 'qeLZEIOrHTN4tsblD1NOLUKsWDQEbnJq6lYOsm5W/50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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