SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9179c79b7915790a2dd8cb50203e04c75a8ba82be1d232e1e28fff5261d1240' 
  AND token = 'B1z1iOR/+poTpKcl/SmYoEucZK6vN7RHOaXujT1VLGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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