SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '12dee854240dcf9338f884af305052396320c6d5269a6fdfaa80eab4b87df275' 
  AND token = '1VQvwU++P8y6H7z3OoZsCwUR0fGiEFw8hiUDWAifOEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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