SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8332f7d2ff5a6de91ce4642e55a74490f64b511ffb63afc49b40753319606571' 
  AND token = '/P6GHzBNR3fM4VDgTbc7bzGw45w/UxBZ9dXV/r7nCmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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