SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc894e9a443295960d8409a4bfcbcf7413423d95c3a0bd1fe718568f436d6667' 
  AND token = 'OF8HqJpYjEXDPuUySLddl+Yw5SgWHdpD9392rJveqfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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