SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6333751e106d8ee85990bd79710307a803037c55157f2fc93e2326c3eb1e9f6b' 
  AND token = 'BCotKZ+WaKGfFLZWUwSmVCVUI0dzbUI7MjnoN6tCJAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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