SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2b361c7ad5e1193aa5a5aa3d48f4f531daee2a240ed16ff629c6b989abf754b' 
  AND token = '4mSH+xaxOdPJplTcHNmUVWerOMP7mkwZbJLWq6IJeAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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