SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7d474d630eae033dac20b7efb5199be0220f338975f81ced1ffad23e90020c4b' 
  AND token = 'chwJva7qdaXn2FVmaIc2gQhyd9H4hjlLZS0j810hyvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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