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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e587acd81cb717c8a82e049e75b5455918f42894ee4a8c834db72b0cdc03cf' 
  AND token = 'AR08l4AERs7k7xLwvTa850mdSjX3tWpxGctXpws21Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}