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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b8893bf83246a6cf2aa892054acc3abc61f2355e0a0da7adf5f97a87165ea262' 
  AND token = '28ACFBn3Ck1TOVX1fcnp1qE0N5qx5NdjsT6U+l9G3zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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