SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78bf968327d731ff0662acfd39e67e471d506ae3f7bc924935fa4c95e7319272' 
  AND token = 'XwunzumGvX2rKzVGjs4BTG9qhuPzmvqdt+3Mx+0fomk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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