SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dc3d6059892e48a1dede0b6e9510b155b90a891772089dcf74201d9615ba1074' 
  AND token = 'L34sBV4SneCBFNywPfbSB7wFklXpZ/+G4dHpxA1bxys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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