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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e889c3dbd6aa3a11fcfd2c9417196e9c206e8edf7f18e2206359df07f02505bb' 
  AND token = 'yD5tei+57CFfrLjR7orUvN6hbpaErGIZxZftxAuEl1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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