SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a86139213d16ed2d42baffad20b047026855823bb512e61bf6c38f44fea6f9a2' 
  AND token = 'Ovmr3hGfKqsxks6D+MzonVejp4GlGA9qkI1ZJ2y0EBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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