SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '74ea3b6681da79ced974161229e32823d5ee197375fa89fc8a6418b4106b09c8' 
  AND token = 'Pm/OZvkTwIx6ljs88WOsNRVmHLBwJoIzcUj4LqcNI10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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