SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e873ccaac2d91d38ee261046540bfa467405d06d90087b0ab7146e9b96046474' 
  AND token = 'HwDJHuEfyTxJ1aiHNmuUR4JgGZRpsVmi+WsPTjK8UcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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