SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd5803b14a8885ace579b6266a92735f5be69cc329f82b12abbcd6f9d8431d17' 
  AND token = 'lEcGWczt5UdOIjxm+u4LaTanWLpcfQwNlIgJuS79dZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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