SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2724b48afd93a47fcd5878508a7c95cc31f6b105e06773a3ebda5e7377aa6e1' 
  AND token = '0Br1uYaxpUtNndTBzygFS2WIouRn0FIylUpuZqzNiYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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