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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a91302df69d157e50044e0fe6e72d996e33586dec2a8d0c46b0d66b770eb857f' 
  AND token = 'q6a1ysPB0sUA5q/CdzR6hYwsvYcTbSy/Ck6h4rcJSxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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