SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '495cbd3ff9e7291d3417251cd61de214bc0b005303351c419bc39b8bc4980ffb' 
  AND token = 'jLfqPpe7SasOW96sIUCJayguyx479k2ESRKR8BIbXzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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