SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8c3319d64b8fbd06edb16e2da6dd93f85821cd7520a1685d52eb1218125ad4bc' 
  AND token = 'A0ZJWLJwtha/VIRYRX7LI8vlziI59wD1CXrtXDHZvCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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