SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6674e5caa288129dc01ea36912efde94ff5f8da8e0004f125a3367a48a758010' 
  AND token = 'D20O56YhZ8KUHox1ajopv6mChlLTBb2DhSLmBzW/gtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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