SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cdb839a3765855640201aea7d2566472b9d75f00fbfa0dc21174a4ea1810e445' 
  AND token = 'OU5qyW9JatIzNFCs8/9ttFK+COUVL6x+lnAfqPKhBAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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