SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b52944abfc865cc157b099858e6a1d23ff1cc92baf3a987c7c263d726dc53a' 
  AND token = 'x+VGds4fhy9+/psgjbYVAQi2hT1H4FVToTB4uZol4JY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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