SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c0dc1d69c66059bfaf2b4a1cb2ac94970285fd8b520ed478934a318e88dcbf2' 
  AND token = 'JNYkUwP/IjLwmvxkCbhiEGx+zJk0x+zqjDQS0VyqtDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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