SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e896402f33f594108b6877cbdb38d808ed2652efa261b56a56749a5e6a62a2a5' 
  AND token = '3Kn+RR0OHJjqiSFrWhaV3462DNquExv8SJozk4XyrCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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