SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8604b3962071ffb5a92bd580169f82932fad30c3024bca99c42532da79a5eff' 
  AND token = 'WmW0KLzpvpaqwMspHk6jDCkQW5KvLUUql6kB5TlatVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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