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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7d3d10a49a52b87f19bfe5bf78cbe4ac925e510e8cef6d7e38f93c43fc02269a' 
  AND token = 'f0fvrUZCoLc/NtBfWQH/fZdUF/usEhj/d4oVmARWrRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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