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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a78a8ba97f22dacd31d6dfa39c2672b4dc5a10b9e93c210c8f4e1a5d1502f8e3' 
  AND token = 'KZXDLYW4n1rz7EJ5fTmnn1eSN+V85CyIs6StFfnjU/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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