SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5e7e2f1f446539af9ceea63f69505d530a1fafaa680ca6458075baede385033' 
  AND token = 'ZZLlaIfm5gxPxsAa+tb9/OCEIFlQjcB+KhzEyaZOAd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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