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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '25e9c952e7c86b72bb8acd4b57dc193becf900ad5ba39396cf7363b3018fdaf2' 
  AND token = 'EIZp1/IyMO3UdEDegNxm0WJsvXyXLJ4XTZ7vMPYTM8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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