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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5de0d9c2bc8e1efd1581a2324440b16d0b752f9550ec35ac31645cd53289ee59' 
  AND token = 'p2zQPttJYmFkfO+Kt2CcvqOXDB+WaJ8BgWjpSFU8Cq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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