SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cadc2f2afd99899621d31d902c1dfee304433559e8e5541c40dd3f37c89324fb' 
  AND token = '5yz31MgIyrTBFpasQOaO9prIgeuB/gpFjifF44PDPpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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