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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87fc3cb4917ea1c15506d146060ad9c81cc7cdfbdec1d94739e5e0dfdcd41bd2' 
  AND token = 'y/MSXjIWsw0tNL60nNq8HcholBFYdQyGYpA/K38BbkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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