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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '88228eecc13231e728d3cdcf433d35e3f4962336f4f13d1644197ef352345e17' 
  AND token = 'FOEXKYRiLlQP+7sAiKgF/XL+WcfSSo7sMTv30GFN33o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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