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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '514acc133f49f497b6c7ee5dfb311ba8bb28b62087bf002f6ae8c9c8e6f0fa6d' 
  AND token = '6/ZbSmVik3iU5h40nIuvPf4Xw6zhdFCceCQpLVaHMOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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