SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c82f73a2dfedae521058e259a87c85f7be2c37968ba8071213c26da4895378a' 
  AND token = 'SDQwT2ggaR8pQpN6tTnCjz1/q4O2xZEr1+paB5Sj85o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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