SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68cc65e349afcfdc3a530afca173a284101c93beb4bd9a177d087cd7945d1855' 
  AND token = 'wXJU+Eiw7dKkgbeoOT0vhQZDkF2X5ub4DwFYTIh6kQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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