SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ed0a8f70053adada00c5af87b661cd36afa360a0ede071a052a576c26922d70' 
  AND token = 'vLPwZgMJ49ymvz6EF6EB+J45x3pHD6W64z7BxCvhT1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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