SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5383e69e1a9d003ded200d7bcee29412adc25f3487bce2b4e0031cda5b6a0690' 
  AND token = 'jhTBESRgvjL79QWsquGC6Vg5TRNJvNtIjzrmVf03WuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}