SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04d73509385aca7a25587213e248a4e758531809251019fb9cd0f6a2ec293474' 
  AND token = 'aeLhQd+RFUxLM1h1jNseZu8kJ+d9Ato+gxPRk5T4Yx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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