SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '838b9ea3ec01bcf7661902ccadba864d3dc4fd1e739ecf63601aad1f329176af' 
  AND token = 'JK+TPB3U1WQs/v2p/1g1acXFkwTbKPEzEPWxmrM75nc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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