SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '424c11b1322c73f4aafc2e48689ca90d70c48aa6fddfcb7e9fee34c5392bccc0' 
  AND token = 'TGN2GIHzNoMSRUPmmP8rlbQkDnK+dYY/+Cac9kzbTSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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