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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b3e5fb49841b2b444cf2921a1e863adf97e2fd65bdba212d8fa3d74c3a4f8424' 
  AND token = 'hK51lVa6SmA4qak7nJZye6k8DOCB4d4yPZ3Amy1e1tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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