SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a232a033cb8c8a5916e74c4ed0d2d884c875d4cbb7535e087da9875b4e427dfd' 
  AND token = 'vhuBhzR/2s46PD5XGVZygb98nFfwXALhLagwChCRszQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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