SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '292f2af6ae003fa221641374ac85df5774fc7037098c32103be67b288f4ba198' 
  AND token = 'lvrTvpT21Jb8E/OGYpwsLFTXt1N8wdjAG1Za3dDwseo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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