SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b3d46a12b55bd3424d967a58d8a7066fc6090f32589f9d8e69eae7e9e10c8d9' 
  AND token = 'HiO+7juaUwh8kXBDswmDHsx7hEbbSL7s4BL1d25sswo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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