SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '51719d217e0484ebaa27062a6bdcc30ab20169dbb86907ff8975a7b3c7d15d62' 
  AND token = '6wrcV//mObv8vDzgRlZgpL/5nYRijDUkrr+ShXUjqFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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