SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13a4dc3731623d2e9b9ae6c9d752431b3c953fd94ed07adcb2be0352d3171545' 
  AND token = '0Bqifuc/orCHRaRsmovo5PHlfVpiBNXLaMHXIJxb0JY=' 
  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"
    }
  }
}