SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38c85b363f04c9c61b17b42681944efe9afba2c488fbfb900efe4289e5dbbb8d' 
  AND token = 'mX4zzJ04106O2UHlmiRCj6MudE5N7EkMGZI3tnBIBFQ=' 
  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"
    }
  }
}