SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37a33e2538688608832cff097766b92f3ea8df810382a84101310f34e5c71fda' 
  AND token = 'VHGt6zDjqmkCzbmE3zNH6NajIiwUASEDw4aQ1rWSfz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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