SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc2f2f3ec9440cd1be4c7880af977fdef0021f363f3e2067db51fe2474c48448' 
  AND token = 'kYwSqZUXfC3aUa1krRvfNYoqyRqY/8v1bIH4KvtasWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}