SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9b95dc9f1571edad0b38e6273c2742bc96e0f01b183783c73b97f51dbeffde4' 
  AND token = '90h64qAlRneuPzq/3KSWxecLKaXmdDiIuZ6bYNhP/dE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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