SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12eb73ffefa6c1f56a9d720345d497086083e296a00f08d6f28fc7612b696806' 
  AND token = 'D1gMW5FGRWtiRQuYKT0jwLYCKHuSBqkrK4S1P/0Xj8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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