SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c90dc86b0d8fe73a8e0899798af74dea2e49abe96dd45f3024917ac15f6ec55d' 
  AND token = 'Rhrl0cgcYD++XoaciVtRBs33vdq1Zd+2AXphyg3QW60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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