SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8687120f9588aff4f987a6d1eb3e14acd0aaad80c20a09b21f6effaf74a9ab3d' 
  AND token = 'itAFuSWD+asRFSheoua6BchDxxFGyjjZqA0Pb6u1l6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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