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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f420cc8a73a9d0858dfc8e11de2b47ca15bb541f84657bb7d717fed19d941e56' 
  AND token = 'UAF2WtjLoi9Bta1M3vBzQtMHSF7T7CmxAkMHZUJPW3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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