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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e0751eaa804fb5b1f4e0d329c621c9c7ddf9a8c2dd7040852d6e7b3ba639116c' 
  AND token = 'ibWgOTeLsnoMw0/jq9n76har+fJV3yeSEMaefKZjItY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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