SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '52a31ad60145848d9c5c72202cd15f9a8a32318fb5a7865d31f324e05859b343' 
  AND token = '/TCJ++TSKyr75BLlTDMi4jl3U9/PFBmt1bz9mtw/ZiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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