SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5be371fc845d7c6f051d10918a93603246fb289008d96281fbd9cf007ea56a31' 
  AND token = 'Ohi2FdJMnuFLcTv5FcBuNHc200xT7XOKfBH9V2zPNEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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