SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68c2e50bedd645e00fbd4b4fc0c9fbc93db54034978d7642dece20755e8db72f' 
  AND token = 'nLNJMpvFK/9alAkWB35/BThNMxCCME3N8BJVK3EyUhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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