SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45c9ff0377851d4e019797986fc7ec29fb497de8db12f885cc27c3ad6e1c79ad' 
  AND token = 'DC3WRDP45yCCGtE+ua05GjkjrgNZBjlvUCeWibNoXKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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