SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7522789ba0130a4672568168d51aeb4a0383f1f881be2363851873eda72a173a' 
  AND token = 'n7CH2oMYGbITqOBw3dWg5CYnnsPct/IM3w92+V7g9ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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